A novel polyacrylic acid/carboxylated nanocellulose fiber/polyethylene glycol hydrogel loaded with nano-ZnO (ZnO-PAA/CNF/PEG: GH-2 (wt(ZnO)% = 12% and wt(PEG)% = 16%)) was synthesized to remove Cr(VI) from wastewater by adsorption synergistic photocatalytic reduction. The effects of ZnO content, PEG content and pH on the removal efficiency of Cr(VI) were investigated. The removal performance and mechanism of Cr(VI) by hydrogels were systematically studied by various techniques. The results showed that when the initial pH = 2, the initial concentration of Cr(VI) = 20 mg/L, the hydrogel dose = 0.5 g/L, and Irradiation power of mercury lamp was 500 W, the removal efficiency of Cr(VI) was 97.22% (dark adsorption for 60 min and photocatalysis for 50 min). The addition of PEG greatly reduced the agglomeration of nano-ZnO in GH-2 and facilitated the separation of photogenerated electron-hole pairs. The adsorption process of Cr(VI) by GH-2 accords with pseudo-second-order kinetics. The photocatalytic process conforms to the pseudo-first-order reaction kinetics. Under the optimal experimental conditions, the removal efficiency of Cr(VI) by GH-2 was still as high as 87.99% after 5 cycles. The removal mechanism of Cr(VI) was mainly through electrostatic attraction, chemical adsorption and photocatalytic reduction. This study provides a feasible method for the synthesis of hydrogel materials with excellent adsorption synergistic photocatalytic performance for the treatment of Cr(VI)-containing wastewater.

中文翻译：

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ZnO-聚丙烯酸/纤维素纤维/聚乙二醇水凝胶高效去除废水中 Cr（VI）：吸附和光催化还原的协同效应


合成了一种负载纳米 ZnO 的新型聚丙烯酸/羧化纳米纤维素纤维/聚乙二醇水凝胶 （ZnO-PAA/CNF/PEG： GH-2 （wt（ZnO）% = 12% 和 wt（PEG）% = 16%）），通过吸附协同光催化还原去除废水中的 Cr（VI）。研究了 ZnO 含量、PEG 含量和 pH 值对 Cr（VI） 去除效率的影响。通过各种技术系统研究了水凝胶对 Cr（VI） 的去除性能和机理。结果表明，当初始 pH = 2，Cr（VI） 初始浓度 = 20 mg/L，水凝胶剂量 = 0.5 g/L，汞灯照射功率为 500 W 时，Cr（VI） 的去除效率为 97.22%（暗吸附 60 min，光催化 50 min）。PEG 的添加大大降低了 GH-2 中纳米 ZnO 的团聚，并促进了光生电子-空穴对的分离。GH-2 对 Cr（VI） 的吸附过程符合准二级动力学。光催化过程符合准一级反应动力学。在最佳实验条件下，GH-2 对 Cr（VI） 的去除效率在 5 次循环后仍高达 87.99%。Cr（VI） 的去除机理主要通过静电吸引、化学吸附和光催化还原。本研究为合成具有优异吸附协同光催化性能的水凝胶材料处理含 Cr（VI） 废水提供了一种可行的方法。